Historical weather data, all-time temperature records, and monthly climate averages for Emmaus, PA. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4th in Emmaus sits squarely in the unpredictable heart of spring — the thermometer has swung from a bitter 20° in 1954 all the way up to 78° in 1950 on this exact date. Today's average high of 57° feels seasonal, but nearly half of all April 4ths here have seen some form of precipitation, so keep an umbrella close.
Emmaus weather does not mess around at the extremes — 78 years of data show a 120-degree spread between the all-time high of 105° on July 3, 1966 and the bone-chilling -15° recorded on January 21, 1994. The area is also no stranger to dramatic events: a single October day in 2005 dumped 8.71 inches of rain, and the January 2016 blizzard buried the area under 30.2 inches of snow.
Emmaus follows a classic mid-Atlantic four-season pattern — summers peak in late July with average highs around 86°, while mid-January bottoms out near 35°. The wettest stretch runs in early August, making late summer the muggiest time to visit. For the most comfortable weather, aim for late May through early June or September, when highs are pleasant and humidity is more forgiving.